1. Field
The present invention relates to urgent deceleration indicating devices and systems and, more particularly to devices and systems that augment existing vehicle braking indicating devices and systems.
2. Related Art
Vehicles have long incorporated brake lights for warning others that the vehicle is decelerating. The brake lights are turned on when the brake pedal is depressed to indicate to the following driver that the vehicle is likely decelerating. However, the brake light merely indicates to the following driver whether the brakes are applied and give no indication as to the urgency of the braking condition or any indication of the magnitude of deceleration of the vehicle. Thus, the following driver must always be alert and realize that any illumination of a vehicle""s brake lights can be a gentle deceleration or a sudden urgent deceleration.
Prior devices and systems have been described that detect and indicate the urgency of a braking condition by illumination of a light. Some of these warning devices are self-contained and include some means for detecting deceleration in the primary direction of vehicle motion. For example, these devices use one or more accelerometers to determine vehicle deceleration in the primary direction of vehicle motion. An indication, such as illumination of the light when the deceleration exceeds a threshold, is then provided.
Because these devices only detect acceleration and only in one direction, they do not measure acceleration independent of gravitational effects and, thus, are prone to false triggers or trigger failures if the vehicle is not in a horizontal orientation when it urgently decelerates. When the vehicle is tilted, e.g., on a slope, the acceleration due to gravity is sensed by the accelerometer, but is assumed to be driver induced by the control circuit of the device. Thus, because of the sensed acceleration due to gravity, these warning devices will cause a false trigger or will fail to trigger such as when the vehicle is travelling up or down a slope.
The prior art also shows that some false triggers or trigger failures may be decreased by warning systems that are responsive to other vehicle operating parameters such as pressure sensed in the hydraulic braking system, wheel velocity or slip sensed by the anti-lock braking system, or distance sensed by a proximity radar system. However, these warning systems are not self-contained, and in addition, require a complex system of multiple sensors with extensive wiring. As result, these warning systems are difficult and costly to manufacture and install, particularly if retro-fitting existing vehicles.
The present invention is therefore directed to a device and system to indicate an urgent deceleration that overcome the above-noted and other disadvantages of prior warning devices and warning systems. The present invention results in a warning device and system that indicate urgent deceleration independent of gravity effects. The device and system are capable of sensing acceleration in at least one direction, for example, the primary direction of vehicle motion and correcting for acceleration forces due to gravity before initiating a warning. In this respect, the Inventors have found that correcting for the acceleration due to gravity, an example of which is described herein, may be employed to render a warning device less prone to false triggering or trigger failures.
In one illustrative embodiment of the invention, an urgent deceleration indicating device to selectively activate a warning indicator is disclosed. A sensor system, having a sensor output, is responsive to acceleration in a primary direction of vehicle motion. A controller responds to the sensor system, corrects for gravitational effects, and initiates at least one warning indicator when the acceleration exceeds at least one threshold value.
In another illustrative embodiment of the invention, a system for indicating an urgent deceleration condition independently of gravity is provided. The system includes at least one warning indicator suitable for mounting to a vehicle. A sensor system, having a sensor output, is responsive to acceleration in a primary direction of vehicle motion. A controller responds to the sensor system, corrects for gravitational effects, and initiates at least one warning indicator when the acceleration exceeds at least one threshold value.
In still another embodiment of the invention, an urgent deceleration indicator is provided. The indicator includes means for indicating a warning and means for detecting acceleration having at least one output. The indicator also includes means responsive to the output of the detecting means. The means for responding also corrects for gravitational effects and initiates the means for indicating when the acceleration exceeds at least one threshold value.
In yet another illustrative embodiment of the invention, a device for use in a vehicle to indicate an urgent deceleration condition independently of gravity is provided. The device includes a base constructed and arranged to mount to the vehicle. The base has a first axis which is substantially alignable with a primary direction of vehicle motion. The base also has a second axis which is different from the first axis. The device also includes at least one sensor mounted to the base for sensing acceleration in the first axis. The device includes a controller which communicates with the at least one sensor and corrects for gravitational effects. The controller initiates at least one warning indicator when the acceleration exceeds at least one threshold value.
In another illustrative embodiment of the invention, a method for indicating an urgent deceleration condition independently of gravity is disclosed. The method includes the step of detecting acceleration substantially in a primary direction of vehicle motion. The method further includes the steps of correcting for effects due to gravity and comparing the acceleration with at least one threshold value. The method further includes the step of initiating at least one warning indicator when the acceleration exceeds at least one threshold value.
In a further embodiment of the invention, a device for use in a vehicle to rearwardly indicate a rapid deceleration of the vehicle is provided. The device includes an elongated array of light emitting diodes extending substantially perpendicular to the longitudinal axis of the vehicle. The device also includes a circuit that has sensor output responsive to acceleration in the direction of the longitudinal axis of the vehicle. The circuit is aligned primarily parallel to and behind the elongated array.
Various embodiments of the present invention provide certain advantages and overcome certain drawbacks of prior devices and systems. Embodiments of the invention may not share the same advantages and those that do may not share them under all circumstances. This being said, the present invention provides numerous advantages including the noted advantage of reducing false triggering or trigger failures.
Further features and advantages of the present invention as well as the structure and method of making various embodiments of the present invention are described in detail below with reference to the accompanying drawings.